Presently, the routine detection of retroviruses in biological samples is only made indirectly by structure-specific (i.e., non-functional) analysis, namely via the detection of viral-specific antibodies and/or individual components (antigens, RNA proviral DNA). Examples of such detection methods are anti-HIV antibody tests, HIV-p24 antigen tests, and HIV-PCR detection test. Holodniy et al., 1991, J. Infect. Dis. 163:862-866; Henrard et al, 1992, AIDS Res. Hum. Retrovir. 8:47-52. This type of analysis is based on a structure-specific molecular interaction between antibody and antigen or PCR primer and proviral DNA. Since it is not testing for viral function, it does not establish the presence of biological intact and functional retroviral particles. Furthermore, this type of analysis does not detect all stages of a viral infection, e.g., the phase in which the infection has already taken place, but antibodies have not yet been generated. These factors can cause both false positive or false negative results.
Accordingly, there is a need for the direct and also functional detection of retroviruses in biological samples. This need is further underscored by the medical and socio-political significance of retroviruses, presently lead by the greatest medical challenge, AIDS, and by an observable increasing tendency and role of retroviruses in animal and human disease (leukemia, auto-immune diseases, cancer, etc.). In addition, the transmissibility of retroviruses by infection poses a serious challenge on the transfusion and transplantation medicine, calling for reliable detection of viral contamination, both for lymph, saliva, sperm or blood samples, and for organs, skin, bone marrow, etc., to be transplanted. The same problem of viral contamination and infection also applies to the use of pharmaceutical preparations and other pharmaceutical/biotechnological or genetechnological preparations with biological origin for treating diseases in human beings and animals, as well as in basic medical research. A prerequisite for a solution to the above-mentioned problems is the direct detection of functional retroviruses by means of a simple, reliable and sensitive method.
Prior to the present invention, the direct and biologically functional detection of retroviruses was only possible in individual cases. It was labor and time intensive, involving the infection of cells using purified virus preparations or cell culture supernatants. Quantitative, simple and reliable routine methods have not existed prior to this invention. This is due to the complex composition of biological samples (blood, organ extracts, etc.) which contain proteins, enzymes, vitamins, lipids, sugars and various inhibitors. They hinder or render impossible the direct and functional detection of retrovirus.
The process of the present invention provides for the routine, direct and biochemically functional detection of retrovirus in biological samples.